The present invention relates to internal combustion engines and in particular to a new high efficiency, low emissions engine.
The automotive industry's answer to improved engine efficiency and low emissions (necessary to meet emission standards) is the computer controlled/catalytic converter rich burning, water cooled gasoline engine, and the diesel engine. The former is very expensive, complex and fuel inefficient, and the latter is also very expensive, complex, heavy and has serious emission problems (soot and NOx). There is a great need for an engine that is highly fuel efficient, cheap, simple and clean. Variations of these two engine types, such as stratified charge engines and fast lean burn engines, are improved systems but still have the shortcomings of requiring high swirl to operate (which reduces efficiency through increased heat transference), computer controlled three-way catalytic converter operation, and conventional cooling systems. Most notable of these are the Honda CVCC engine, the May Fireball, and the Nissan Naps-Z engine.
There is much prior art on improving ignition of very lean mixtures. For the present purposes, Ward and Wu, Plasma Jet Ignition, U.S. Pat. No. 4,317,068 discloses an improved ignition system for igniting lean mixtures. Ward, U.S. Pat. No. 4,297,983 discloses a system for application to the engine design disclosed here, which is capable of actually stimulating the burn so that the lean limit of flammability is extended and the flame speed is increased by electrical (microwave) means.
Prior art on operating an engine adiabatically exists, such as Automotive Engineering, June 1978, "Insulated Pistons Raises Diesel Efficiency"; SAE Paper 810070, 1981, "Cummins-Taradcom Adiabatic Turbocompound Engine Program"; Popular Science, December, 1982, "From Japan's Labs-Ceramic Diesels". However, all this prior art is on the adiabatic deisel. It is generally conceded that adiabatic operation is not possible for the premixed, homogeneous charge spark ignited (gasoline) engine. The reason given is that at the higher operating temperatures associated with adiabatic operation serious knock (detonation) problems would ensue so that the engine simply would not run.